Image:Women eventually got the vote after years of campaigning and protests

Women voters had to be over 30 and either a member - or married to a member - of the Local Government Register; a property owner; or a graduate voting in a university constituency.

It took another 10 years for full equal voting rights for all men and women over the age of 21 – except of course for lunatics, prisoners and members of the House of Lords who were excluded.

Britain wasn't quite the first modern society to give women the vote.

That was New Zealand, which is now heading for another record as its new Prime Minister, Jacinda Ardern, is due to have a baby while in office.

But the UK was in the lead in 1969 when the Labour government dropped the voting age from 21 to 18 years old.

I used to enjoy meeting the late Screaming Lord Sutch on the election trail.

He liked to point out that when he started campaigning in 1963, votes at 18 were considered a Monster Raving Loony Party idea, only to be put into law later - along with pubs open all day.

Image:Lord Sutch's Monster Raving Loony Party championed lowering the voting age to 18

But the battle over rights to vote is never over.

This week's PMQs took place in the absence of the party leaders and the debate was dominated by whether the voting age should be dropped from 18 to 16.

David Lidington and Emily Thornberry, who stood in for May and Corbyn, were widely praised for conducting an informed debate rather than trading irrelevant abuse and statistics as the party leaders tend to.

Labour's Thornberry asked: "At 16, we are free from parental control, we can leave home, we can start a family, we can get married, we can start work, we can pay taxes and we can join the forces, so can he give us a logical explanation of why a 16-year-old should not have the right to vote?"

The Tory Cabinet minister replied that 18 was generally considered to be the age of majority when people become adults and that "it was the last Labour Government who raised the legal age for buying cigarettes to 18, raised the age for selling knives to 18, raised the age for buying fireworks to 18 and raised the age for using a sunbed to 18".

There is certainly a logical inconsistency between protecting teenagers because they are not considered capable of protecting themselves, and giving them the vote.

Yet most politicians, including those who are against it, predict that 16 and 17-year-olds will soon have the franchise.

Personally, I can see advantages in putting off the full responsibilities of adulthood for a bitAdam Boulton

Labour, the Greens, the SNP and the Liberal Democrats are all in favour and so is Ruth Davidson, the leader of the Scottish Conservatives.

The SNP government gave over-16s the vote in the 2015 and Davidson says her mind was changed by how they behaved.

They turned out in large numbers, 75%, like other voters, and crucially for her, Davidson noted, they did not all stampede to back Yes.

The 18 to 25 age group are traditionally the laziest voters, but there's some evidence that those still in school are more informed and take their democratic responsibilities more seriously than those of student age.

I suspect that most of the parties backing a lowering of the voting age are doing it for selfish reasons because they think they would get an electoral advantage.

If all youngsters were to vote the same way, they could be right.

The Office for National Statistics says that they would have made up 2.87% of the voting population at the last election. That would have been enough to overturn the results in 88 constituencies, including marginal seats in Scotland and the Midlands.

My guess is that they wouldn't make that much difference, since they wouldn't vote for the same side in a herd.

The handful of countries where the under-18s have voting rights are a mixed bag; including Austria, Argentina, Brazil, Cuba, Ecuador, Nicaragua, Indonesia, Guernsey and both Koreas.

Will the UK still be joining them?

Personally, I can see advantages in putting off the full responsibilities of adulthood for a bit.

When I was a teenager I was more angry about being banned from (arthouse) X-films than I was about not having a vote, even though I was interested in politics.